Exactly How Many Calories You Should Eat at Lunch to Lose Weight

If you're trying to lose weight, you've probably packed a Mason jar salad with a side of celery sticks for your midday meal more than once. But according to new research, your low-cal lunch might actually be working against you.

A new study published American Journal of Clinical Nutrition found that eating the bulk of your daily calories at lunch, as opposed to dinner, can help you lose weight over time.

For the study, researchers recruited 80 overweight and obese women between the ages of 18 and 45, and had them eat their biggest meal of the day (50 percent of their daily calories) at either dinner or lunch for 12 weeks. So their diet broke down like this: 15 percent of their calories at breakfast, 15 percent as a snack, 50 percent at lunch (or dinner), and 20 percent at dinner (or lunch).

What does that translate to, exactly? Though each participant's diet was based on her specific calorie needs, a woman on a 1,500-calorie per day diet would be eating 225 calories at breakfast, another 225 as a snack, 750 calories at lunch, and 300 calories at dinner (or vice versa). That's a giant lunch, ya'll.

In addition to divvying up their calories in a specific way, the women ate a diet that was high in carbs and low in saturated fat. More specifically, 17 percent of their calories came from protein, 23 percent from fat, 60 percent from carbs, and 400 grams (which is a little less than a pound) came from fruits and veggies for fibre. (Start working toward your weight-loss goals with Women's Health Summer Training Guide)

They were also asked to do 60 minutes of “moderate activity” (like brisk walking) five days a week.

Compared to the group who ate 50 percent of their calories at dinner, the lunch crew had a higher average weight loss—about 6.5kg vs. 4kg—and a greater reduction in BMI.

So why is a huge lunch better for weight loss than a ginormous dinner? The study authors suggest that the real reason the lunch group dropped more kilos is because their fasting insulin levels were lower compared to those who ate a majority of their calories at night. As a result, the lunch group kept their blood sugar spikes in check—meaning, they didn't feel super hungry again shortly after eating.

While the weight loss is impressive, it’s worth pointing out that study participants were overweight or obese to begin with. If you aren’t, it’s unlikely you would lose as much weight in such a short period of time on this eating plan.

However, the study raises a good point: Making lunch your big meal of the day, and scaling back on dinner can help keep your weight in check, and may even help you drop kilos.